Protein export is a process whereby protein that has been manufactured in a cell is routed to the surface of the cell. Export of proteins occurs in all microorganisms, but has been particularly well-studied in certain species of bacteria and yeast.

The ability of a cell to export protein is crucial to the survival or pathogenicity of the cell. Bacteria that have protein appendages for movement (e.g., flagella) and attachment (e.g., pili), and protective protein surface coatings (e.g., S layers) depend on the efficient export of the proteins. Exotoxins that are ultimately excreted by some bacteria need to get across the cell wall before being released from the bacterium.

Defects in protein export can produce or contribute to a number of maladies in eukaryotic cells including human cells (e.g., cystic fibrosis, diabetes, osteopororsis).

A general feature of protein export is the manufacture...